.\"
.\" Copyright (c) Mark J. Kilgard, 1996.
.\"
.TH glutSpaceballButtonFunc 3GLUT "3.8" "GLUT" "GLUT"
.SH NAME
glutSpaceballButtonFunc - sets the Spaceball button callback for the current window. 
.SH SYNTAX
.nf
.LP
void glutSpaceballButtonFunc(void (*func)(int button, int state));
.fi
.SH ARGUMENTS
.IP \fIfunc\fP 1i
The new spaceball button callback function. 
.SH DESCRIPTION
glutSpaceballButtonFunc sets the Spaceball button callback for the
current window. The Spaceball button callback for a window is called
when the window has Spaceball input focus (normally, when the mouse
is in the window) and the user generates Spaceball button presses. The
button parameter will be the button number (starting at one). The
number of available Spaceball buttons can be determined with
glutDeviceGet(GLUT_NUM_SPACEBALL_BUTTONS). The state is
either GLUT_UP or GLUT_DOWN indicating whether the callback was due
to a release or press respectively. 

Registering a Spaceball button callback when a Spaceball device is not
available is ineffectual and not an error. In this case, no Spaceball button
callbacks will be generated. 

Passing NULL to glutSpaceballButtonFunc disables the generation
of Spaceball button callbacks. When a new window is created, no
Spaceball button callback is initially registered. 
.SH SEE ALSO
glutSpaceballMotionFunc, glutSpaceballRotateFunc, glutMouseFunc, glutButtonBoxFunc, glutTabletButtonFunc, glutJoystickFunc, glutDeviceGet
.SH AUTHOR
Mark J. Kilgard (mjk@nvidia.com)
